Catalytic Performance Of Catalysts Used For Preparing Cyclohexanedimethanol By Catalytic Hydrogenation Of Tpa

The catalyst preparation and catalytic performance of terephthalic acidas raw material to prepare1,4–cyclohexanedimethanol in two sectionswas studied in this paper.The impact of the carrier, load method of active substance, the Ru/Sn molar ratio, calcination temperature and dosage of NaBH4in catalystpre-reduction process to catalytic hydrogenation performance ofRu-Sn-B/γ-Al₂O₃catalyst and Ru-Sn-B/mordenite catalyst wasinvestigated in this paper. The results show that hydrogenation ofcatalysts prepared by γ-Al₂O₃and mordenite as carrier is better and theappropriate preparation conditions was obtained: both catalysts wasimpregnated with load order of the tin-ruthenium-boron by distributionimpregnation, calcined at500℃,（?）：, Wt%（Ru）=8,and respectively Ru/Sn molar ratio of the Ru-Sn-B/andRu-Sn-B/mordenite catalyst is1.4and1. Meanwhile, reactiontemperature, pressure and catalyst loading was investigated.When Wt% （Ru）is8,reaction temperature and pressure of the first stage is150°C,60bar and reaction temperature and pressure of the second stage is230°C,100bar, conversion of TPA of the catalytic hydrogenation ofterephthalic acid to prepare1,4–cyclohexanedimethanol byRu-Sn-B/γ-Al₂O₃catalyst and Ru-Sn-B/mordenite catalyst can bothreach nearly100%, the yield of CHDM can respectively reach86.3%and73.5%, and anti-cis ratio of product can respectively reach1.56and2.42.Catalysts prepared by two kinds of carrier were characterized by BET,X-ray diffraction （XRD） and Temperature-programmed reduction （TPR）test means in this paper. Analysis of the BET and TPR results show thatcatalyst activity is impacted by interaction between Sn and aluminagreatly, meanwhile specific surface area of catalyst has a certain extentaffect on activity of catalyst; BET results also shows anti-cis ratio of theproduct is affected by pore size distribution of the catalyst, When thecatalyst pore size distribution concentrated in the mesoporous range, theeffect of catalyst on selection of the product is obverse, and anti-cis ratioof the product is high. In addition, the XRD analysis results show that tinis present on the catalysts surface in the form of microcrystalline ofSnO₂,and ruthenium and boron is present on the carrier surface in theform of amorphous of RuB and has good distribution.